# Copyright (c) 2014, Fundacion Dr. Manuel Sadosky
# All rights reserved.

# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:

# 1. Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.

# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.

# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import logging

from barf.core.reil import ReilImmediateOperand
from barf.core.reil import ReilLabel
from barf.core.reil import ReilMnemonic
from barf.core.reil import ReilRegisterOperand
from barf.core.reil.builder import ReilBuilder
from barf.core.reil.helpers import to_reil_address
from barf.utils.utils import VariableNamer

logger = logging.getLogger(__name__)


class TranslationError(Exception):
    pass


class FlagTranslator(object):

    def __init__(self, arch):
        self.__arch = arch
        self.__flags = {}

    def __getattr__(self, flag):
        return self.__get_flag(flag)

    def __getitem__(self, flag):
        return self.__get_flag(flag)

    # Auxiliary functions
    # ======================================================================== #
    def __get_flag(self, flag):
        flag = flag.lower()

        if flag not in self.__arch.registers_flags:
            raise TranslationError("Invalid flag")

        if flag not in self.__flags:
            self.__flags[flag] = ReilRegisterOperand(flag, self.__arch.registers_size[flag])

        return self.__flags[flag]


class RegisterTranslator(object):

    def __init__(self, arch):
        self.__arch = arch
        self.__registers = {}

    def __getattr__(self, register):
        return self.__get_register(register)

    def __getitem__(self, register):
        return self.__get_register(register)

    # Auxiliary functions
    # ======================================================================== #
    def __get_register(self, register):
        register = register.lower()

        if register not in self.__arch.registers_gp_all:
            raise TranslationError("Invalid register")

        if register not in self.__registers:
            self.__registers[register] = ReilRegisterOperand(register, self.__arch.registers_size[register])

        return self.__registers[register]


class InstructionTranslator(object):

    def __init__(self):
        # An instance of a *VariableNamer*. This is used so all the
        # temporary REIL registers are unique.
        self._ir_name_generator = VariableNamer("t", separator="")

    def translate(self, instruction):
        """Return REIL representation of an instruction.
        """
        try:
            trans_instrs = self._translate(instruction)
        except Exception:
            self._log_translation_exception(instruction)

            raise TranslationError("Unknown error")

        return trans_instrs

    def reset(self):
        """Restart REIL register name generator.
        """
        self._ir_name_generator.reset()

    def _translate(self, instruction):
        raise NotImplementedError()

    # Auxiliary functions
    # ======================================================================== #
    def _log_not_supported_instruction(self, instruction):
        logger.info("Instruction not supported: %s (%s [%s])",
                    instruction.mnemonic, instruction,
                    instruction.bytes.encode('hex'), exc_info=True)

    def _log_translation_exception(self, instruction):
        logger.error("Error translating instruction: %s (%s [%s])",
                     instruction.mnemonic, instruction,
                     instruction.bytes.encode('hex'), exc_info=True)


class TranslationBuilder(object):

    def __init__(self, ir_name_generator, architecture_information):
        self._ir_name_generator = ir_name_generator

        self._instructions = []

        self._builder = ReilBuilder()

        self._arch_info = architecture_information

    def add(self, instruction):
        self._instructions.append(instruction)

    def temporal(self, size):
        return ReilRegisterOperand(self._ir_name_generator.get_next(), size)

    def immediate(self, value, size):
        return ReilImmediateOperand(value, size)

    def label(self, name):
        return ReilLabel(name)

    def instanciate(self, address):
        return self.__resolve_loops(address, self._instructions)

    # Auxiliary functions
    # ======================================================================== #
    def __resolve_loops(self, address, instrs):
        # Collect labels.
        idx_by_labels = {}
        instrs_no_labels = []
        curr = 0

        for i in instrs:
            if isinstance(i, ReilLabel):
                idx_by_labels[i.name] = curr
            else:
                instrs_no_labels.append(i)
                curr += 1

        instrs[:] = instrs_no_labels

        # Resolve instruction addresses and JCC targets.
        for index, instr in enumerate(instrs):
            instr.address = to_reil_address(address, index)

            if instr.mnemonic == ReilMnemonic.JCC:
                target = instr.operands[2]

                if isinstance(target, ReilLabel):
                    addr = to_reil_address(address, idx_by_labels[target.name])
                    size = self._arch_info.address_size + 8

                    instr.operands[2] = ReilImmediateOperand(addr, size)

        return instrs
